A team of astronomers have found what could be one of the universe’s oldest stars, almost entirely made of materials formed by the Big Bang.

Residing in the same part of the Milky Way galaxy as our own solar system, the star is believed to be up to 13.5 billion years old which is evidenced by its extremely low metal content, or metallicity, Xinhua news agency reported.

According to co-author Andrew Casey, it was previously believed that the first stars that formed in the universe could not possibly still exist today.

“The findings are significant because for the first time we have been able to show direct evidence that very ancient, low mass stars do exist, and could survive until the present day without destroying themselves,” Casey said.

According to co-author Andrew Casey, it was previously believed that the first stars that formed in the universe could not possibly still exist today. VOA

The metallicity of stars increases as they are born and die, in a cycle which results in the creation of more and more heavy metals, with the Earth’s sun being around 100,000 generations down that line and holding a metal content roughly equal to 14 Jupiters.

Stars created at the beginning of the universe, however, would have consisted entirely of elements like hydrogen, helium and small amounts of lithium – meaning the extremely low metallicity of the newly discovered star, about the same as the planet Mercury.

This suggests that it could be as little as one generation removed from the beginning of the universe, the researchers noted.

Up until around 1990, scientists believed that only massive stars could have formed in the early stages of the universe, and could never be observed because they burn through their fuel so quickly and die.

However, the new study has shown that it is possible for low mass stars to last as long as the 13 billion years since the Big Bang — Red Dwarf stars for instance, which have a fraction of the mass of the sun, are thought to live for trillions of years. (IANS)

The measurement includes all the stars and planets, dust and gas, as well as the four-million-solar-mass supermassive black hole at the center. Pixabay

Using data from NASA’s Hubble Space Telescope and the European Space Agency’s Gaia satellite, astronomers have come up with one of the most accurate measurements of mass of the Milky Way galaxy.

While previous research dating back several decades provided estimates for our galaxy’s mass, ranging between 500 billion to three trillion solar masses, according to the latest measurements, Milky Way weighs about 1.5 trillion solar masses (one solar mass is the mass of our Sun).

The measurement includes all the stars and planets, dust and gas, as well as the four-million-solar-mass supermassive black hole at the center.

“We want to know the mass of the Milky Way more accurately so that we can put it into a cosmological context and compare it to simulations of galaxies in the evolving universe,” said Roeland van der Marel of the Space Telescope Science Institute (STScI) in Baltimore, Maryland.

The more massive a galaxy, the faster its globular clusters move under the pull of gravity, according to a forthcoming paper in The Astrophysical Journal. Pixabay

To weigh the galaxy, the team augmented Gaia measurements for 34 globular clusters out to 65,000 light-years, with Hubble measurements of 12 clusters out to 130,000 light-years that were obtained from images taken over a 10-year period.

They also measured the three-dimensional movement of globular star clusters – isolated spherical islands each containing hundreds of thousands of stars each that orbit the center of our galaxy.

The more massive a galaxy, the faster its globular clusters move under the pull of gravity, according to a forthcoming paper in The Astrophysical Journal.

The new mass estimate puts our galaxy on the beefier side, compared to other galaxies in the universe. The lightest galaxies are around a billion solar masses, while the heaviest are 30 trillion, or 30,000 times more massive.

The Milky Way, the galaxy which contains Earth’s solar system, is home to up to 400 billion stars and an estimated 100 billion planets. (IANS)